High Lead Exposures Resulting from Pottery Production in a Village in Michoacaân State, Mexico
Total Page：16
File Type：pdf, Size：1020Kb
Journal of Exposure Analysis and Environmental Epidemiology (1999) 9, 343±351 # 1999 Stockton Press All rights reserved 1053-4245/99/$12.00 http://www.stockton-press.co.uk High lead exposures resulting from pottery production in a village in MichoacaÂn State, Mexico ROBIN HIBBERT,a ZHIPENG BAI,b JAIME NAVIA,c DANIEL M. KAMMENa,d AND JUNFENG (JIM) ZHANGb a Science, Technology and Environmental Policy (STEP) Program, Woodrow Wilson School of Public and International Affairs, Princeton University, Princeton, New Jersey 08544-1013 b Environmental and Occupational Health Sciences Institute, UMDNJ-Robert Wood Johnson Medical School and Rutgers University, 170 Frelinghuysen Road, Piscataway, New Jersey 08854 c Grupo Interdisciplinario de TecnologIÁa Rural Apropiada (GIRA), AC, Apartado Postal 158, PaÂtzcuaro, MichoacaÂn 61609, Mexico d Energy and Resources Group (ERG), University of California, Berkeley, Berkeley, California 94720-3050 This paper reports findings from a screening study conducted to examine potential lead (Pb) exposures in residents of a Mexican village where Pb oxide continues to be used in ceramic pottery production. Extremely high Pb concentrations were measured in personal and indoor air samples, household surface dust samples, and household soil samples. Personal air Pb concentrations for workers performing pottery firing and glazing were up to 454 g/m3. Results from indoor air samples indicate that airborne Pb concentrations were lower during nonglazing period compared to the glazing period. Soil Pb concentrations measured in 17 homes ranged from 0.39 to 19.8 mg/g. Dust Pb loading on surfaces of household items, hands, and clothes of a worker ranged from 172 to 33 060 g/f t 2. Pb content as high as 2.4 g/g was found in a bean stew cooked in a pot made in the village. Based on these Pb concentrations measured in multiple media and data adapted for exposure contact rates, we have made rough estimates of Pb exposures via inhalation, soil/dust ingestion, and food ingestion. Estimated total daily Pb intake, on average, is 4.0 mg for adults and 3.4 mg for children living in the village. In the total daily intake, a greatest fraction may be contributed by food ingestion and another significant fraction may come from soil/dust ingestion for the children. Although the sample size is small, these measurements indicate a very significant public health problem for the village residents and a large number of other similar communitiesin Mexico. (It was estimated that there are approximately 1.5 million glaze potters.) The Pb exposure is implicated in a number of pervasive health problems in the region, and is the cause for national and international attention. Several recommended solutions to this problem range from personal protection and behavioral changes to introduction of alternative glazes. Keywords: ceramic glaze, Mexico, Pb exposure, Pb poisoning, pottery. Introduction the US. This unfortunate fact resulted in the Centers for Disease Control and Prevention (CDC) lowering the acceptable blood lead (BPb) level three times in the last Lead (Pb) is a well-known toxic substance. Due to its 20 years (CDC, 1991). The current action level for BPb is toxicity and environmental prevalence, Pb poisoning has 10 g/dl. Since principal Pb sources such as leaded gasoline been one of the worst environmental threats to children in and Pb-based paints have been removed in the US, a dramatic decrease in BPb levels was reported from 12.8 to 2.8 g/dl between 1976±1980 and 1988±1991 (Harrison 1. Abbreviations: AIHC, American Industrial Health Council; ASTM, American Society for Testing and Materials; BPb, blood lead; CDC, and Laxen, 1981; Pirkle et al., 1994). Most significantly, the Centers for Disease Control and Prevention; DHHS, US Department of percentage of US children aged 1±5 years with BPb levels Health and Human Services; EOHSI, Environmental and Occupational 10 g/dl or greater dropped from 88.2% to 8.9%. This may Health Sciences Institute; EPA, US Environmental Protection Agency; look like a signal for declaring victory in the war against Pb FAA, flame atomic absorption; HUD, US Department of Housing and poisoning. One might hesitate to do so, however, by Urban Development; ICP-MS, inductively coupled plasma-mass spectro- metry; ISO, International Standard Organization; NIST, National Institute examining Pb exposures of some specific populations in of Standards and Technology; Pb, lead. some parts of the world (Diaz-Barriga et al., 1997; 2. Address all correspondence to: Junfeng (Jim) Zhang, Ph.D., Exposure Murgueytio et al., 1998). Measurement and Assessment Division, Environmental and Occupa- A recent study (Fernandez et al., 1997) showed that tional Health Sciences Institute, UMDNJ-Robert Wood Johnson Medical measured BPb levels of ceramic workers in three villages in School and Rutgers University, 170 Frelinghuysen Road, Piscat- away, NJ 08854. Tel.: (732)445-0158. Fax: (732)445-0116. E-mail: MichoacaÂn State of Mexico significantly exceeded US [email protected] recommended safety level of 10 g/dl. The mean BPb Revised 14 December 1998; accepted 23 December 1998. values for 310 female and 146 male workers were 22.9 and Hibbert et al. High lead exposures resulting from pottery production in a village in MichoacaÂn State, Mexico 23.9 g/dl, respectively. The study, however, included area, which was also an area where children frequently blood samples from residents who did not work with pottery played on the soil floors. A stainless steel spoon was used to in their homes and those who used closed gas ovens in scrape the sample from the ground and then the sample was determining community and age/gender-stratified averages. placed in a Ziploc bag. The soil samples were dried for Therefore, BPb levels for pottery workers might be even analysis at 438C in an oven for 1 week. Portions between 0.2 higher than the community averages reported by Fernandez and 0.8 g were weighed and placed into test tubes (Oak et al. Ridge Centrifuge Tube, 30 ml). The soil samples were then Although Fernandez et al. (1997) found high BPb levels, digested in a microwave oven using a total Pb digestion no environmental exposure data were collected as part of method described by the Department of Housing and Urban their study. Environmental data are particularly useful in Development (HUD, 1990). The microwave oven (CEM providing insights into exposure pathways, and for making MDS-2000) was set at 81% power and the digestion time recommendations on reduction of Pb exposure and thus was 23 min. Pb concentrations were determined using reduction of BPb level. In those Mexican villages where flame atomic absorption (FAA) spectrometer (Perkin-Elmer residents make a living with pottery production, raw Model 3100) at the wavelength of 283.3 nm. The analytical materials used to glaze pottery contain Pb oxide powder detection limit of the FAA was 0.5 ppm. which can be easily spread and are accessible to both adults and children (Avila et al., 1991; Fernandez et al., 1997). Therefore, the village residents may receive Pb exposures Dust Samples The dust samples were obtained using a through many or all of the following major pathways: (a) commonly used method which consisted of wiping areas of inhalation of Pb-containing airborne particles; (b) ingestion known size with commercially available moist towelettes of Pb-contaminated dust and soils; and (c) ingestion of Pb- (Thomas and Spiro, 1994; Orlova et al., 1995). The size of contaminated water and food. In the present study, we have the area was usually estimated in the present study, because therefore collected data on each of these Pb exposure flat continuous areas such as tabletops usually did not exist pathways through a methodology that includes samples in the sampled homes. Typical surfaces sampled were taken from air, dust, soil, and foods in Pb-containing boards for tortilla production, water jugs, shelves, and pottery. This program provides a unique set of insights and utensils. Hands and clothing of people loading the kiln or thus also recommendations on how to reduce Pb exposures glazing were also sampled for dust. According to previous resulting from the pottery production and use. studies using this dust collection method, this method may underestimate the Pb loading (Chavalitnikul and Levin, 1984). After drying in the laboratory, each towelette was Methods placed in a 120-ml digestion liner with 30 ml of 20% nitric acid added and then digested in the CEM microwave. After Study Location and Population the digestion, 30 ml of deionized water were added to the The present study was carried out in the village of Santa Fe sample, and any undissolved towelette residues were de la Laguna (referred to here as `Santa Fe'), MichoacaÂn, removed. Although a tiny amount of the residue was Mexico. The village contains about 950 homes averaging observed, it was felt that the digestion was sufficient to free six persons each. Samples were collected in 17 homes in this the Pb from the wipe matrix. Pb concentrations were village over a 5-week period in July and August of 1996. determined using the same FAA technique as for the soil The 17 homes were selected on the basis of their pottery samples. firing. All homes sampled had soil floors, low walls that allowed passage of air from one room to another, and at most one spigot of running water. The roofs were of varying Air Samples Samples of airborne respirable suspended heights, and usually allowed the smoke to flow into particles (RSP<7.1 m in aerodynamic diameter) were neighbors' homes or into adjoining rooms. The PaÂtzcuaro collected during the glazing and firing of the pottery, using lake region is the site of our ongoing investigation of the an SKC Aircheck pump, cyclone attachment, and 0.5 m environmental and health impacts of biomass and bioenergy matched weight filters.